This invention relates to a suspension system for a vehicle and more particularly to an improved vehicle suspension system for interrelating the operation of the suspension elements for two of the wheels of the vehicle.
It is well known to employ a suspension system for suspending each wheel of the vehicle for suspension movement relative to the vehicle body. Conventionally, the suspension system for each wheel includes a shock absorber which is intended to control the damping functions of the movement of the wheel relative to the vehicle. However, the damping system for the vehicle wheel must damp a number of different types of motions.
For example, when the wheel travels along the road as the vehicle moves and an obstacle in the road is encountered, the suspension system permits the wheel to move relative to the body so as to dampen the shock of the road encounter. These forces are, for the most part, transmitted in a vertical direction and are due to the magnitude of the obstruction in the road. However, there are also inertial forces on the vehicle body that tend to cause the body to move relative to the wheel. For example, when rounding a corner, there will be a swaying motion from one side to the other about a longitudinal axis. In addition, when braking or accelerating or under other conditions, there will be a pitching about a transversely extending axis. If these additional motions are also damped by the suspension system, the degree of damping is basically the same regardless of the way in which the load is encountered. That is, the damping force for damping the condition when a road obstacle is encountered is the same as the damping force which is generated when there are swaying or pitching motions. Of course, it is desirable to provide a suspension system wherein the actual type of damping encountered will depend upon the way on which the load that tends to cause relatively movement between the wheel and the vehicle body is encountered. Said another way, it is generally desirable to provide a suspension system for a vehicle wherein the damping will be dependent upon the type of load encountered and the reason why the load is generated.
It is also a well known fact that the loads applied to the wheels and vehicle body are not completely isolated from each other. That is, road obstacles are encountered when rounding curves, accelerating or decelerating. Hence, it is not possible to isolate the particular type of load encountered so as to provide the optimum degree of damping dependent upon the load source.
It is, therefore, a principle object to this invention to provide an improved suspension system for a vehicle wherein the suspension system can respond to different types of loads which are encountered as the same time and provide the proper damping for each load.
As a specific example, when rounding a corner, it is generally to avoid too much leaning of the body relative to the wheels. It has been proposed, therefore, to provide a stiffening action to the rolling motion under these circumstances. However, this solution to the problem is not necessarily the optimum.
For example, if the dynamic sway stiffness is too great, then there is an increased total load on the outer wheels which can present problems. This is particularly true with respect to the front wheel when entering a corner and the rear wheel when accelerating under leaving a bend.
It is, therefore, a still further object to this invention to provide an improved arrangement for interrelating the operation of the suspension system so as to provide appropriate damping under all conditions and to reduce loads on the wheels caused by inertial forces.
In addition to the foregoing criteria, it is also desirable to insure that the shock absorber mechanism itself is relatively simple and can be easily adjusted. That is, although various complicated systems have been provided for shock absorber control, the more complicated the system the more difficult it is to manufacture and adjust properly. In addition, the control for varying conditions can become complex.
In accordance with another feature of the invention, therefore, it is a further object to this invention to provide an improved and simplified shock absorber control system for a vehicle.